Consensus protocol for blockchain structure

ABSTRACT

A non-monetary incentive model defines a Distributed Consensus Protocol (DCP) for a blockchain based on a proof-of-play mining approach. The non-monetary incentive model employs a gamification approach where mining efforts are recorded responsive to achievement in a gaming environment, rather than the proof-of-work or proof-of-stake approaches commonly used for blockchain valuation. The incentive model draws on a participant volition in attaining or improving a gaming achievement. The approach records gaming moves or actions undertaken by a participant playing the game, based on a seed used to instantiate the game. Upon attaining a predetermined minimum score, and at a predefined difficulty, the gaming effort is deemed to warrant a new block in the blockchain.

BACKGROUND

Cryptocurrency defines an electronic monetary medium backed by a numberof participants, rather than a governmental sovereign as withtraditional currency. Cryptocurrency provides a digital currency ordigital token with a recognized value for use by members of an on-linecommunity via a global computer network. Cryptocurrency incorporates anelectronic ledger in conjunction with cryptographic protocols to ensureauthenticity and non-repudiation by storing a sequence of transactionusing encryption techniques to ensure that undetected changes areprevented. Encryption, typically via public-key encryption methods,imposes data manipulations that are computationally infeasible toreverse, or “hack.” A blockchain is a structure that defines such anelectronic ledger for implementing a digital currency or digital tokensuch that participants accessing the blockchain may verify activities ofothers and may not make undetected changes to the blockchain.Blockchains thus incorporate cryptographic protocols to operate andbuild applications relying on a verifiable ledger on a decentralizedcomputer platform for a set or sequence of transactions that cannot berepudiated or changed anonymously. A blockchain employs a DistributedConsensus Protocol (DCP) to bind the participants of the blockchain to arecognition of value defined therein, just as a bank statement itemizesrecognized value because people trust the bank.

DCPs use challenge mechanisms of various sorts to limit how fast newblocks are added to the blockchain. Value is defined by mechanisms likeproof-of-work or proof-of-stake in blocks and/or transactions added tothe blockchain based on efforts or status of a miner. Other mechanismsfor electronic currency/valuation may also be employed. A miner may onlyadd a new block if they have successfully met or solved a currentchallenge imposed by the DCP. In Bitcoin and many related DCPs, forexample, the challenge is to produce a cryptographic hash with a certainnumber of leading 0 bits.

SUMMARY

A non-monetary incentive model defines a Distributed Consensus Protocol(DCP) for a blockchain based on a Proof-of-Play mining approach. Thenon-monetary incentive model employs a gamification approach wheremining efforts are recorded responsive to achievement in a gamingenvironment, rather than proof-of-work or proof-of-stake as commonlyused for blockchain valuation. The incentive model draws on aparticipant volition in attaining or improving a gaming score. Theapproach records gaming moves or actions undertaken by a participantplaying the game, based on a seed used to instantiate the game. Uponattaining a predetermined minimum score, and at a predefined difficulty,the gaming effort is deemed to warrant a new block in the blockchain.Trivial or insufficient gameplaying efforts are screened by the minimumscore and difficulty. Verification is provided by the recordation of thegaming moves or actions in playing the game, as the gaming instance isrepeatable using the same seed with the replayed gaming moves togenerate the same score, or result.

Configurations herein are based, in part, on the observation thatblockchains derive value from a DCP among many participants whorecognize the value defined in the blockchain. A blockchain with too fewparticipants or a low or non-existent recognition of value is of littleuse. Unfortunately, conventional approaches to blockchain technologyrely on monetary incentive models such as attributing a monetary valuein the form of the blockchain's currency or token to participants whoproduce blocks in the blockchain. Participants achieve value bydemonstrating sufficient proof-of-work in solving computationalchallenges, or proof-of-stake in owning or controlling a large and/orold quantity of blockchain currency or tokens. Accordingly,configurations herein substantially overcome the shortcoming ofconventional monetary incentive models by defining a Proof-of-Playincentive model that draws participants by a desire to achieve at agame, rather than a desire to attain monetary value.

In an electronic transaction environment, a blockchain is a verifiableelectronic ledger defining a sequence of blocks containing transactions,in which the sufficiency of the electronic ledger is based on adistributed consensus protocol (DCP) common to a plurality ofinterconnected computing nodes. A non-monetary incentive model is basedon a gamification incentive medium. A miner, player or participantinvokes the incentive medium (game) for an interactive exchange, suchthat the gamification incentive medium is recognized by the DCP foradding transactions to the electronic ledger. Configurations discussedherein discuss a “blockchain” as the implementation of an electronicledger and associated transactions. Alternate implementations for acryptographically secure ledger may be employed; blockchains define asequence of blocks and added blocks may denote new value.

Configurations herein employ a “Proof-of-Play” incentive model as analternative to conventional proof-of-work or proof-of-stake. Gamingachievement, typically expressed as a score in the game, is soughtrather than finding a challenge that satisfies a number of leadingzeros, for example. The precise details of a Proof-of-Play scheme arespecific to a particular game, but in general a player/miner, inlaunching and playing the game, directs the node to perform in a certainmanner (via game inputs) on behalf of the player to generate a result,or score.

In the course of playing the game, a node computes a seed for derivingan instantiation of the incentive medium, and receives a sequence ofgaming inputs, or “moves”, directed to the incentive medium as the minerplays the game. The game is responsive to the sequence of inputs forgenerating a result based on the seed and the sequence of inputs. Uponcompletion of the instantiation, the node evaluates the generated resultagainst a publication criteria for entry in the electronic ledger. Ifthe result satisfies the publication criteria, analogous to a challengein conventional blockchains, the node stores the seed and the sequenceof inputs by creating a new block in the blockchain. The validity forpublication of the block is verifiable based on a reiteration of thegame using the seed and the sequence of inputs for attaining the sameresult.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following description of particularembodiments of the invention, as illustrated in the accompanyingdrawings in which like reference characters refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating the principles ofthe invention.

FIG. 1 is a context diagram of a computing environment suitable for usewith configurations herein;

FIG. 2 shows a sequence of invoking an incentivization medium in theenvironment of FIG. 1 ;

FIG. 3 shows a data and process flow of additions to an electronicledger based on the incentivization medium of FIG. 2 ;

FIG. 4 shows a data and process flow of verification of blocks added tothe electronic ledger as in FIG. 3 ; and

FIGS. 5A-5C show a flowchart of electronic ledger propagation using theincentivization medium as in FIGS. 1-4 .

DETAILED DESCRIPTION

In the discussion that follows, an extension of conventionalproof-of-work/stake DCPs defines Proof-of-Play as an incentive model fora blockchain. Blockchains preserve information, typically itemizedvalues, in a series of blocks and transactions covered by cryptographicoperations that make it computationally infeasible to make unauthorizedand/or undetectable changes to the transactions therein. Blockchainstherefore define a trusted electronic ledger of transactions, analogousto a bank statement, that derives trust from cryptography rather than abank's security and reputation. Example configurations below depictgameplaying as a non-monetary incentivization model based on playing agame, rather than monetary rewards. The gamification incentive model maybe employed with any suitable game, skill exhibition or competition thatis expressible in computer-received moves or steps, and that enticesparticipants based on largely intangible “rewards” in terms ofsatisfaction or accomplishment at achieving in the game. Configurationsherein employ TETRIS® and Minetest as a gamification medium, althoughany suitable exhibition of skill and/or strategy may be employed.

Conventional Distributed Consensus Protocols incentivize participationby offering a monetary reward for performing certain actions. Bitcoin,for example, currently rewards the miner of each block with 12.5Bitcoins, which can then be spent or exchanged for other currencies.Monetary incentivization is a natural fit for cryptocurrencies, whichaim to create a decentralized monetary system. For non-cryptocurrencyDCP applications, however, a monetary rewards scheme is often a strongimpediment to adoption, as it complicates the incentive model.Participants in such a DCP are incentivized to mine both by monetaryrewards and by the intended benefits of the DCP, which may not becomplementary. Miners participating purely for the monetary rewards maythus crowd out miners primarily interested in the DCP's intended use.

Configurations herein propose an alternative DCP incentive model thatincentivizes mining purely with the intrinsic reward of playing a game.Instead of proof-of-work or proof-of-stake, this scheme isProof-of-Play. Proof-of-Play complements a DCP with associated miningand verification schemes. Proof-of-Play is a modular component that canbe used as the basis for new DCPs or integrated into existing protocols,therefore it can replace monetary incentive models in conventional DCPssuch as used in Bitcoin.

Participants in a Proof-of-Play DCP are incentivized to mine by theirdesire to play the associated game on its own merits, without referenceto the DCP itself. No DCP-specific rewards (such as blockchain tokenslike Bitcoins) for successful block mining are thus required,eliminating via demotivation whole categories of malfeasance. Unlikeproof-of-work, which mines new blocks with a probabilisticallyguaranteed quantity of work, or proof-of-stake, which mines new blockswith sortition weighted by quantity and quality of stake, Proof-of-Playmines new blocks with a probabilistically guaranteed quantity andquality of play.

FIG. 1 is a context diagram of a computing environment suitable for usewith configurations herein. In a computing environment 100, a pluralityof nodes 110-1 . . . 110-3 (110 generally) are interconnected by apublic access network 120 such as the Internet. Each of the nodesincludes an interface for communicating with other nodes 110 via thenetwork 120. Consensus protocols require wide engagement to preservesecurity. Participants each control and/or operate at least one node inthe network, and “mine” by pursuing an ability to add additional blocksto a blockchain. Conventional DCPs incentivize miners 122 with monetaryrewards. Monetary rewards are incentivizing because they have a basic,almost universal, appeal. An alternate DCP incentivization modelprovides a means of creating large-scale permissionless distributedconsensus protocols without resorting to paying participants.Configurations herein present gamification of the incentive model toreplace proof-of-work with Proof-of-Play, such that miners play and thusmine for the intrinsic fun of a game, not extrinsic monetary rewards.

In a blockchain 130, a miner 122 is incentivized to “mine,” or createnew blocks. A blockchain application 124 launched on a node 110 underthe control of the miner 122 executes for mining new blocks according tothe incentivization protocol defined for the blockchain 130. Inconventional approaches, this is proof-of-work or proof-of-stake asdefined by the DCP corresponding to the blockchain. In theconfigurations discussed below, Proof-of-Play denotes mining efforts forcreation of a new block.

The Proof-of-Play approach provides an alternate mining method with anovel associated incentive model for a Distributed Consensus Protocol.Proof-of-Play improves on conventional mining methods such as hash-basedproof-of-work and proof-of-stake by detaching the incentive to mine fromthe functionality of the DCP. Participants in a Proof-of-Play DCP areincentivized to mine by their desire to play the associated game on itsown merits, without reference to the DCP itself.

Proof-of-Play quantifies blockchain mining interactions in terms ofgaming performance. In an example herein, Tetris serves as anappropriate gamification incentive due to its longstanding appeal,skill-based nature and single player format. Other suitable games may beemployed. To add/gain value and add a new block B4, a participantlaunches (plays) the game via the application 124 and the controller123, and upon sufficient achievement (defined further below), is deemedto have mined the block B4. The block B4 is added to the blockchain 130that already includes blocks B1 . . . B3. The permissionless,distributed and verifiable properties of the blockchain preserves themined value of the added block B4. Subsequently, node 110-3 desires toverify the contents of the blockchain 130. Verification of any of theblocks B1 . . . B4 may be performed by any of the nodes 110. The minedvalue denoted in B4 can be verified by any of the nodes and notundetectably altered by any of the nodes. The record of thetransactions/contents of B4 do not directly accrue to the miner as‘value,’ as in conventional blockchains, but rather the immutability andrecognition of blockchain ambiently provides value to all its usersincluding the miner 122.

FIG. 2 shows a sequence 200 for invoking an incentivization medium inthe environment of FIG. 1 . Referring to FIGS. 1 and 2 , a miningsequence 210 and a verification sequence 220 are shown. A miner 122(player) initiates a new game instance at 211 via the application 124,which operates as the blockchain client. The game instantiation is basedon a seed generated for the new game instance at 212. The precisedetails of a Proof-of-Play scheme are specific to a particular game, butgenerally share three components. First, a procedural generationalgorithm that takes a seed value as input and creates an instance ofthe game based on that seed. This algorithm should be deterministic—thesame seed value must always produce precisely the same instance. Thisrequirement limits the set of games usable with Proof-of-Play to thosethat could or already incorporate such repeatability. Second, a gameplaylog that stores all player moves during each instance of the game.Finally, a score (or similar output value) that can be derived byapplying the moves or player inputs in a gameplay log to the gameinstance generated by the algorithm from a particular seed value.

The player plays the game and their moves/actions such as keystrokes orjoystick/button manipulations are recorded at 213. Upon completion at214, a score and log of player inputs performed to achieve the score arestored. A predetermined minimum score ensures that trivial gameplayingefforts are not rewarded with new blocks, so a check is performedagainst this minimum score at 215. If the score is insufficient, theplayer is free to play again at 211. If the score meets thepredetermined minimum, a further check may be performed based on achallenge mechanism. For example, the publication criteria may alsoinvolve a hash validation (452, FIG. 4 ) or other challenge similar toconventional Bitcoin challenges that require a certain number of leadingzeros.

DCPs use challenge mechanisms of various sorts to limit how fast newblocks are added to the blockchain. A miner may only add a new block ifthey have successfully met or solved a current challenge imposed by theDCP. In Bitcoin and many related DCPs, for example, the challenge is toproduce a hash with a certain number of leading 0 bits. In order toensure a constant mining rate as the size and power of the mining poolchanges, many DCPs also implement a difficulty adjustment algorithm thatdynamically alters the difficulty of the challenge (e.g. increasing ordecreasing the number of leading 0 bits required) based on, e. g. thestate of the blockchain. As a modular incentive model with definedmining and verification mechanisms, Proof-of-Play supports but does notrequire a challenge mechanism or difficulty adjustment algorithm.Proof-of-Play produces varied inputs to the challenge mechanism withvalues derived from game instances (instead of the random nonces used inBitcoin, etc.) and gives verifiers a method for validating that minersproduced their solutions through legitimate play.

In Proof-of-Play players, who need not know or care that they areparticipating in a DCP, independently create and play instances of thegame. Depending on the selected gamification medium (e.g. Tetris), aninstance may be as small as a single game action or as large as anentire session of play. In the course of play, the game nodes 110 usethe Proof-of-Play scheme to generate output values as potentialsolutions to the current DCP challenge. This process is analogous tominers in a conventional DCP such as Bitcoin generating random noncesand checking the resulting block header hashes. If a player's instancesolves the challenge, their client (node 110) then broadcasts the seedand gameplay log in the block header for a proposed new block on theblockchain 130 for verification by other nodes 110.

If the DCP incorporates a challenge mechanism that defines a difficultyfor publishing a new block, the client checks the score and seed/nonceagainst that difficulty at 216 (the seed is derived from the nonce toprovide a value in a suitable form/type as needed to instantiate thegame). If the score and seed satisfy the challenge mechanism check, thenthe client creates a new block including the nonce and the gameplay logand propagates the new block at 217. The score does not need to beexplicitly stored in the block because the score can be recreated fromthe seed and gameplay log.

At 220, a blockchain including the newly added block may be verified byany node 110 in the network. Verifiers verify a block (e.g. B1, B2, B3,B4, . . . ) in the blockchain by using the seed in the block header tocreate a matching instance of the game, applying the actions from thegameplay log in the block header to it, and confirming that theresulting output value/score meets the DCP minimum and passes thedifficulty check imposed by the DCP's challenge mechanism, if any. Inone configuration, by combining the game score with a challenge result,Proof-of-Play can be deployed as a modular drop-in replacement for theincentivization model and verification scheme in preexisting DCPimplementations such as the Bitcoin protocol. Alternatively, theProof-of-Play incentivization model can support a separate DCP thatoperates only on the achieved gaming score, discussed further below. Anode 110 receives the new block B4 for verification from the network 120at 221. The verifying node 110 recreates the game instance using theseed/nonce to instantiate the game at 222 and applies the gameplay logof inputs/moves at 223. The resulting score is checked against thepredetermined minimum at 224, and if successful, the verifier checks thescore and seed/nonce against the difficulty at 225 and verifies theblock at 226. If either the score or the seed/nonce difficulty (hashchallenge 452) checks fail, the verifying node 110 rejects the new blockat 227.

FIG. 3 shows a data and process flow of additions to an electronicledger based on the incentivization medium of FIG. 2 . Referring toFIGS. 1-3 , a player/miner 122 invokes a new instance of a game (Tetris)via node 110-4. A different nonce 310 is employed to generate a seed 312used by the game for each different instantiation. The seed is typicallya value derived from at least a portion of the nonce to match the formexpected by the game for initializing its randomness. A processor in thenode 110-4 launches an instance 320 of Tetris. The sequence of moves orinputs 324 received by the node 110-4 on behalf of the player/miner 122are stored in the gameplay log 330 as they are delivered to the gameinstance 320 during play. Upon completion, the resulting score 340 andgameplay log 330 undergo evaluation according to the publicationcriteria needed to qualify for entering a new block. In other words, ifthe gameplaying experience was not noteworthy (did not achieve at leastthe predetermined minimum score, and hash-based challenge if included),it will not pass the publication criteria.

FIG. 4 shows a data and process flow of verification of blocks added tothe electronic ledger as in FIG. 3 . Referring to FIGS. 1-4 , theblockchain 130 includes blocks denoting a series of transactions thattogether form a persistent ledger protected against unauthorized and/orundetectable modification by cryptographic structures, typically basedon public key signatures and secure hashes. The general notion of ablockchain provides an electronic ledger defined by blocks andtransactions; various extensions on or alterations to the headerstructure shown in FIG. 4 may be implemented without departing from theincentivization model as defined herein. Blockchain infrastructurerelies on the public key signatures for providing non-repudiation andthe hashes for providing immutability and modification detection. Eachblock includes a header 430 including several cryptographic fields 412,a timestamp 414, a difficulty 416, nonce 418, a minimum score 420 and agameplay log 422.

The cryptographic fields 412 along with the nonce 418, support thecryptographic infrastructure for authentication and nonrepudiation ofthe transactions in the blockchain. The timestamp 414 is used forordering of added blocks because the blockchain propagation may notnecessarily be sequential. In implementations where a hybrid publicationcriteria is employed, the difficulty 416 defines a further conditionsuch as a number of leading zeros or other qualifier in a proposedsolution in addition to the minimum score needed for publication. Thiscan be used to make sure the gamification of the incentive modelrestricts excessive creation of new blocks, i.e. does not make miningtoo “easy.” The nonce 418 is a unique or single use number supportingcryptographic operations and is also used as a random basis for seedgeneration. The minimum score 420 is a value that the miner/player needachieve in Tetris or other selected incentive medium to qualify toproduce a new block. The stored gameplay log 422 is the verificationcopy of the series of moves or inputs stored from the gameplay log 330.

For verification, the nonce 418 is used to derive the seed 312, and thestored gameplay log 422 is applied to a non-interactive instantiation320′ of the game. If the resulting score and/or other outputs meets thepublication criteria (score minimum and/or difficulty), the block isdeemed valid.

FIGS. 5A-5C show a flowchart 500 of electronic ledger propagation usingthe incentivization medium as in FIGS. 1-4 . Referring to FIGS. 1-5C, inthe computing environment 100 having a verifiable electronic ledger suchas the blockchain 130 defining a sequence of transactions, an incentivemodel is based on an incentive medium. Reliance on the unmodifiablenature of the electronic ledger is based on a distributed consensusprotocol (DCP) common to a plurality of interconnected computing nodes110. In other words, users “trust” the DCP much as conventional currencyis based on a trust in the nation that issued it.

To commence a mining session or effort, a miner (player or participant)invokes the incentive medium for an interactive exchange, in which theincentive medium is recognized by the DCP for adding blocks oftransactions to the electronic ledger, depicted at step 501. Theincentive medium is defined by a launchable application responsive tothe seed 312 for deterministically generating the same result over anynumber of instantiations based on the seed and corresponding sequence ofinputs defined in the gameplay log 330, as disclosed at step 502. Theexample incentive medium is an instantiation 320 of a game such asTetris. Invoking the incentive medium includes performing an interactiveexchange of values in response to an application generated,deterministic result defined by the seed and the sequence of inputs,depicted at step 503. The incentive medium may be satisfied by alaunchable application, typically expressed as an executable file, forrendering an instantiation of the launched application for invoking theseed for generating a deterministic instantiation. This means that thesame sequence and timing of inputs provided to a gaming instantiationwith the same seed will produce the same score (result). The exampleinteractive exchange includes the gaming mechanics of Tetris (othergamification approaches could be employed), defined by keystrokes and/orjoystick inputs for rotating a falling object according to precisetiming to achieve a well-defined agglomeration of shapes. In the exampleshown, therefore, the launchable application is a gaming applicationresponsive to the seed for rendering a gaming scenario, in which thesequence of inputs define gaming moves for attaining a score definingthe result, wherein a Proof-of-Play is established by the sequence ofinputs recorded in the gameplay log 330, as shown at step 504.Gamification of the incentive medium is beneficial because aninteractive gaming application is quantitatively responsive to a timingand substance of the inputs in the sequence of inputs for increasing ascore value defining the result.

The client or host defined by the node 110 computes a seed for derivingan instantiation of the incentive medium, as depicted at step 505. Thisincludes generating the seed 312 from a nonce 310 that differs in eachinstantiation of the incentive medium and storing the nonce inconjunction with the sequence of inputs in the electronic ledger toallow replay and verification, as shown at step 506. In a typicalblockchain implementation, the nonce and log are stored in a new blockwhich is only added to the blockchain (the electronic ledger) when it ispublished and verified. As used herein, the nonce is an absolutelyrandom value picked independently by the client within the constraintsof use and form as defined by the DCP. The nonce may therefore bederived by a blockchain infrastructure or application such as thatemployed in Bitcoin. Alternatively, other blockchain architectures orapproaches may be employed to derive a seed via alternate mechanisms. Insimplest terms, the seed is a random value that determines the course ofplay for generating different gaming scenarios, but the same seed willgenerate (repeat) the same game.

Once launched, during interactive gameplay, the node 110 receives asequence of inputs directed to the incentive medium, such that theincentive medium is responsive to the sequence of inputs for generatinga result based on the seed and the sequence of inputs, as depicted atstep 507. The gaming application responds to the user's inputs or“moves” according to the game dynamics, which often require skill,dexterity and timing which contribute to the value and enjoyment ofProof-of-Play.

Upon game completion, a score results, and the node 110 evaluates thegenerated result against publication criteria for entry in theelectronic ledger, as disclosed at step 508. Blockchain entries derive avalue from an effort, challenge or difficulty in creating new blocks.This may include the resulting score alone, or may include a challengecombined with the score, to regulate and “throttle” the ease with whichnew blocks may be created. Use of a challenge also facilitates the useof Proof-of-Play with existing blockchain mechanisms which employ achallenge as part of their infrastructure. If, at step 509, thepublication criteria includes a hash based challenge defined as the hashvalidation 452, then the publication criteria includes a minimum scoredefining a minimum value for the result, and a difficulty indicative ofan effort expended in attaining the result, as depicted at step 510.

Evaluation includes comparing the result to the publication criteria bycomputing a hash of a combination of the score and the seed used toinstantiate the incentive medium and comparing the hash to thedifficulty (if called for), as depicted at step 511. An illustrationdepicting a Tetris-based challenge may be as follows:

1. Miners play Tetris, seeding the game with SHA-256(block header),where ‘SHA-256’ denotes the application of the standardizedcryptographic hash of that name and changing nonce (within the blockheader) between games to give each game a unique seed.

-   -   a. Miners keep a gameplay log of all player actions during the        game.

2. At the end of the game, if

-   -   (score>minimum and SHA-256(score || seed)<difficulty), where        ‘||’ denotes concatenation    -   insert gameplay log into the block header and broadcast the new        block for verification.

3. Nodes 110 accept and propagate new blocks if they pass verification.Verification is performed as follows:

-   -   a. Calculate seed=SHA-256(block header) and instantiate a Tetris        game with seed.    -   b. Perform a “play-through” following the gameplay log to        confirm score>minimum.    -   c. Confirm SHA-256(score || seed)<difficulty.

Note again that in Proof-of-Play there is no monetary reward forsuccessful miners—miners mine because they enjoy playing Tetris on itsown merits and their playing of Tetris thus powers the mining process.The example given here is adapted for integration with a Bitcoinblockchain infrastructure and employs the Bitcoin block headerstructure, but Proof-of-Play is a drop-in replacement for proof-of-workand can be used in any proof-of-work-based system—Proof-of-Play isagnostic as to the types of transactions and overall structure of theDCP it powers. Finally, recall that in the block header of FIG. 4 , thedifficulty may emanate from a Bitcoin implementation and is a dynamicvalue that controls how often the network produces a new block whereasthe minimum is a fixed value added to support Proof-of-Play in Tetris.The difficulty defines a predetermined number of leading zeros and thecomputed hash has a number of leading zeros for comparison, such thatthe comparison matches when the hash has at least as many leading zerosas the difficulty.

Alternatively, at step 513, if the publication criteria includes onlythe achieved Tetris score, and not the hash validation 452, then thenode 110 compares the result to the predetermined minimum score 420. Acheck is performed, at step 512, to determine if the result satisfiesthe publication criteria, as shown at step 512. If not, the miner mayreturn to play another time, as disclosed at step 514.

If the publication criteria is satisfied, a new block is published bystoring the seed and the sequence of inputs in the block and thenappending the block to the electronic ledger, such that the publicationis verifiable based on a reiteration of the instantiation of theincentive medium using the seed and the sequence of inputs for attainingthe same result, as depicted at step 515.

The node 110 publishes the new block in the electronic ledger that isthe blockchain 130 after storing the new block in the electronic ledger,as depicted at step 516. This renders the electronic ledger resistant toundetected modification. The electronic ledger is a blockchain 130defined by a series of blocks, in which each block in the series iscryptographically related to at least one other block in the series ofblocks, and each block is verifiable by a recipient based on the DCP, asshown at step 517. Any unpublished changes to one of the blocks in theseries of blocks would be detectable based on the DCP.

Subsequently, as the blockchain 130 propagates around nodes 110 in thenetwork 120, nodes may invoke a verification of the newly added block,as disclosed at step 518. The verifying node 110 launches aninstantiation of the incentive medium based on the seed stored inrelevant block in the electronic ledger, as depicted at step 519, andprovides the sequence of inputs corresponding to the seed to theincentive medium for generating a result using the published sequence ofinputs 330.′ The node confirms that the generated result satisfies thepublication criteria, as depicted at step 521. The verification willcomplete because the seed combined with the moves from the sequence ofinputs 330′ will produce the same score that previously satisfied theminimum, and the nonce will result in the same hash (if employed) thatwas used for publication at step 511. If the verification does not pass,then an unauthorized intervention or breach is suspected, as shown atstep 522.

Another gamification configuration employs Minetest as theincentivization medium. Minetest is an open-source highly-modifiablereimplementation of the popular game MINECRAFT®. In Minetest, playerscan create and run their own servers via P2P networking. It ismultiplayer, deterministic, and adaptable to the blockchain. The gameworld is procedurally generated from a seed value via a deterministicalgorithm, and each “chunk” of the world is generated from just its X, Ylocation and the world seed. Minetest is also widely accessible on avariety of platforms for a large potential player base, and has a strongfollowing, as people want to play and enjoy playing the game of theirown volition.

Minetest players either start their own servers to host worlds or playas clients of existing servers. In a given Minetest world, when a newchunk (gaming unit or element) is generated (e.g. as a result of playerexploration), the server hashes the chunk. Alternatively, the chunk canbe hashed when it is modified by a player (e.g. by the addition of newMinetest blocks). If a chunk hash is less than the current difficulty,the server has successfully mined and broadcasts the new block to thenetwork, adding its world seed and chunk location to the block header,similar to the block header 430 in FIG. 4 , above. The network verifiesthe new block by using the published world seed and chunk location toindependently generate the chunk and check its hash.

Those skilled in the art should readily appreciate that the programs andmethods defined herein are deliverable to a user processing andrendering device in many forms, including but not limited to a)information permanently stored on non-writeable storage media such asROM devices, b) information alterably stored on writeable non-transitorystorage media such as floppy disks, magnetic tapes, CDs, RAM devices,and other magnetic and optical media, or c) information conveyed to acomputer through communication media, as in an electronic network suchas the Internet or telephone modem lines. The operations and methods maybe implemented in a software executable object or as a set of encodedinstructions for execution by a processor responsive to theinstructions. Alternatively, the operations and methods disclosed hereinmay be embodied in whole or in part using hardware components, such asApplication Specific Integrated Circuits (ASICs), Field ProgrammableGate Arrays (FPGAs), state machines, controllers or other hardwarecomponents or devices, or a combination of hardware, software, andfirmware components.

While the system and methods defined herein have been particularly shownand described with references to embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made therein without departing from the scope of theinvention encompassed by the appended claims.

What is claimed is:
 1. In an electronic transaction environment having averifiable electronic ledger, the sufficiency of the electronic ledgerbased on a distributed consensus protocol (DCP) common to a plurality ofinterconnected computing nodes, a method of implementing an incentivemodel based on an incentive medium, comprising: invoking the incentivemedium for an interactive exchange, the incentive medium recognized bythe DCP for adding blocks to the electronic ledger; computing a seed forderiving an instantiation of the incentive medium; receiving a sequenceof inputs directed to the incentive medium, the incentive medium definedby an interactive gaming exchange and responsive to the sequence ofinputs for generating a result based on the seed and the sequence ofinputs; evaluating the generated result against a publication criteriafor entry in the electronic ledger, the publication criteria including aminimum score defining a minimum value for the result, and a difficultyindicative of an effort expended in attaining the result; and, if theresult satisfies the publication criteria, storing the seed and thesequence of inputs as a block in the electronic ledger, the blockverifiable based on a reiteration of the instantiation of the incentivemedium using the seed and the sequence of inputs for attaining the sameresult.
 2. The method of claim 1 further comprising verifying the blockby: launching an instantiation of the incentive medium based on the seedstored in the electronic ledger; providing the sequence of inputscorresponding to the seed to the incentive medium for generating aresult; and confirming that the generated result satisfies thepublication criteria.
 3. The method of claim 1 wherein the incentivemedium is defined by a launchable application responsive to the seed fordeterministically generating the same result over a plurality ofinstantiations based on the seed and corresponding sequence of inputs.4. The method of claim 3 further comprising generating the seed from anonce that differs in each instantiation of the incentive medium, andstoring the nonce in conjunction with the sequence of inputs in theelectronic ledger.
 5. The method of claim 1 wherein invoking theincentive medium includes performing an interactive exchange of valuesin response to an application generated, deterministic result defined bythe seed and the sequence of inputs.
 6. The method of claim 1 whereinthe incentive medium is an interactive gaming application, theinteractive gaming application qualitatively responsive to a timing andsubstance of the inputs in the sequence of inputs for determining ascore value defining the result.
 7. The method of claim 1 furthercomprising publishing the electronic ledger including the block afterstoring the block in the electronic ledger, the electronic ledger beingresistant to undetected modification.
 8. The method of claim 7 whereinthe electronic ledger is a blockchain defined by a series of blocks,each block in the series cryptographically related to at least one otherblock in the series of blocks, each block verifiable by a recipientbased on the DCP and published or unpublished changes to one of theblocks in the series of blocks detectable based on the DCP.
 9. Themethod of claim 5 wherein the incentive medium is a launchableapplication for rendering an instantiation of the launched applicationinvoking the seed for generating a deterministic instantiation.
 10. Themethod of claim 9 wherein the launchable application is a gamingapplication responsive to the seed for rendering a gaming scenario, thesequence of inputs defining gaming moves for attaining a score definingthe result, wherein a proof-of-play is established by the sequence ofinputs.
 11. The method of claim 1 further comprising comparing theresult to the publication criteria by computing a hash of a combinationof the score and the seed used to instantiate the incentive medium; andcomparing the hash to the difficulty.
 12. The method of claim 11 whereinthe difficulty defines a predetermined number of leading zeros and thecomputed hash has a number of leading zeros for comparison, thecomparison matching when the hash has at least as many leading zeros asthe difficulty.
 13. A proof-of-play blockchain structure, comprising: averifiable electronic ledger defining a sequence of blocks, thesufficiency of the electronic ledger based on a distributed consensusprotocol (DCP) common to a plurality of interconnected computing nodes,the ledger including a plurality of blocks, each block having a header;a nonce in the header for varying instantiations of an incentive mediuminvoked for adding additional blocks to the ledger, the incentive mediumdefined by an interactive gaming exchange; a sequence of inputs in theheader, the sequence of inputs provided to the incentive medium in aninstantiation based on the nonce; a minimum result in the header, theminimum result indicative of a result to be achieved with aninstantiation of the incentive medium in order to add a new block to theledger, the minimum result based on a minimum score and a difficultyindicative of an effort expended in attaining the result, the nonce andsequence of inputs defining a proof-of-play incentivization metric. 14.The blockchain structure of claim 13, further comprising a reward metricfor encouraging participation by the computing nodes based on aninteractive game launchable on the interconnected computing nodes, theinteractive game defined by an executable computer file.
 15. Theblockchain structure of claim 13, further comprising: a created blockfor addition to the blockchain; a verification node responsive to thecreated block, the verification node for launching an instantiation ofthe incentive medium based on the seed stored in the electronic ledger,providing the sequence of inputs corresponding to the seed to theincentive medium for generating a result, and confirming that thegenerated result satisfies the publication criteria.
 16. The blockchainstructure of claim 13 wherein the incentive medium is a launchableapplication for rendering an instantiation of the launched applicationinvoking the seed for generating a deterministic instantiation.
 17. Theblockchain structure of claim 16 wherein the launchable application is agaming application responsive to the seed for rendering a gamingscenario, the sequence of inputs defining gaming moves for attaining ascore defining the result, wherein a proof-of-play is established by thesequence of inputs.
 18. The blockchain structure of claim 15 wherein theblockchain defined by a series of blocks, each block in the seriescryptographically related to at least one other block in the series ofblocks, each block verifiable by a verification node based on the DCPand unpublished changes to one of the blocks in the series of blocksdetectable based on the DCP.
 19. A computer program embodying programcode on a non-transitory medium that, when executed by a processor,performs steps for implementing a method of implementing an incentivemodel for a distributed consensus protocol (DCP) common to a pluralityof interconnected computing nodes based on an incentive medium, themethod comprising: invoking the incentive medium for an interactiveexchange, the incentive medium recognized by the DCP for adding blocksto the electronic ledger; computing a seed for deriving an instantiationof the incentive medium; receiving a sequence of inputs directed to theincentive medium, the incentive medium defined by an interactive gamingexchange and responsive to the sequence of inputs for generating aresult based on the seed and the sequence of inputs; evaluating thegenerated result against a publication criteria for entry in theelectronic ledger, the publication criteria including a minimum scoredefining a minimum value for the result, and a difficulty indicative ofan effort expended in attaining the result; and, if the result satisfiesthe publication criteria, storing the seed and the sequence of inputs asa block in the electronic ledger, the block verifiable based on areiteration of the instantiation of the incentive medium using the seedand the sequence of inputs for attaining the same result.
 20. The methodof claim 1, further comprising receiving the sequence of inputsresulting from interactive gaming inputs or moves directed towards anexecutable entity defining the incentive medium, the publicationcriteria defined by achievement of a predetermined score resulting fromthe gaming inputs or moves.